[Bug]: Table of Contents (TOC) Title is editable but is overwritten on update

[gorgenarrows]

Operating system

Fedora release 41

Publii version

0.46.3 (build 17008)

Post editor

WYSIWYG editor

Bug description

The Table of Contents (TOC) section allows the title (initially "Table of Contents") to be edited, however when the update icon is pressed, any changes are lost.

When scanning through other TOC related issues, I saw that the TOC plugin is provided by TinyMCE. When I look at their latest version of the plugin (https://www.tiny.cloud/docs/tinymce/latest/tableofcontents/), the title is preserved across updates.

Steps to reproduce

1. Create a new post.
2. Insert some headers and content.
3. Insert a TOC
4. Change the TOC title from "Table of Contents" to "Whatever".
5. Perform the update action on the TOC.

My expectation is that the title still says "Whatever", but it is changed back to "Table of Contents".

Relevant log output